SAMPLING EOREUMA-LOFTINI (LEPIDOPTERA, PYRALIDAE) ON TEXAS SUGARCANE

Sugarcane fields of different types were sampled for 3 yl to determine the seasonal density, spatial dispersion, and within-field stratifica tion of larvae and pupae of Mexican rice borer, Eoreuma loftini (Dyar) . Population density never exceeded 1.0 larva per stalk in any year. R atoon fields of sugarcane regrowth averaged more larvae per stalk than plant cane or hot water-treated fields. There was a trend for hot wat er-treated fields to contain a higher proportion of younger larvae tha n other fields, an indication that infestations in hot water-treated f ields come from moths migrating into the fields rather than from local ized infestations from planted billets. Greater numbers of older larva e and pupae were found later in the season than earlier. There was mor e stalk-to-stalk and field-to-field variation in larval dispersion tha n among blocks, tiers, or plots within fields. Sample sizes for use in estimating E. loftini larval density with a defined level of reliabil ity are presented.